Drinking Water Treatment Unit Certification

The water treatment business is growing rapidly and all signs point to a continued steady growth. As new technologies emerge, the already complicated business of selling water treatment equipment becomes more complex. For you, the dealer, the task is one of sorting out the facts on each line of water treatment products and choosing the product lines that will meet the needs of your specific locale. Each of you is familiar with the water quality problems in your area, but finding a line of equipment that you can have faith in, that is reliable and consistently performs as claimed, may not be as easy as it first appears.

One tool available to you is looking for products which have been certified. The certification mark is the symbol to look for to provide you with that assurance. You can look for this mark on the lines of water filters you carry as a guarantee that the products you are placing in consumer homes actually reduce specific contaminants to the claimed capacity. At the same time, you can be sure that these filters do not, in and of themselves, add any harmful (health-related) substances to the water.

The certification program for Drinking Water Treatment Units (DWTUs) notifies you and your customers that the water filters you carry have been evaluated and tested by an independent, third-party certification organization. Products are certified against one (or more) of six American National Standards/NSF Standards for Drinking Water Treatment Units. These standards have been
developed through a consensus process involving all parties of interest-regulatory, user/consumer groups, and industry-who have agreed upon minimum design and performance criteria that specific technologies of drinking water treatment systems must achieve.

The six standards for Drinking Water Treatment Units are


  • Standard 42: Drinking water Treatment Units-Aesthetic Effects,

  • Standard 44: Cation Exchange Water Softeners,
  • Standard 53: Drinking Water Treatment Units-Health Effects,
  • Standard 55: Ultraviolet Microbiological Water Treatment Systems,
  • Standard 58: Reverse Osmosis Drinking Water Treatment Systems, and
  • Standard 62: Drinking Water Distillation Systems.

    All standards are public documents and any manufacturer may self-certify that a product meets any one of these standards. However, there is a difference between products that are certified by NSF and those "Tested to NSF Standards." When a product bears the mark for a specific standard, NSF assures that it complies with the following requirements specified in the Standard:

    • Verification of manufacturer's contaminant reduction claim(s),

  • Toxicological review of all materials that come in contact with the drinking water to assure that the product itself is not adding any harmful substances to the water,
  • Structural integrity testing to assure that the product will function in its intended end-use application, and
  • Review of advertising, literature and labeling to assure performance claims are not misleading.
  • How can you as a dealer have the assurance that the product submitted for testing is in fact the product that is being marketed? You must answer this question as well as all of the above issues if the product lines you carry have been evaluated by outside organizations.

    The certification program is not simply a "snapshot" of a product's performance. Following the initial evaluation of material, design and construction and testing against the entire standard, unannounced audits are conducted at the manufacturing location to assure that no changes or modifications have been made to the certified product.

    Periodically, product samples are collected for retesting to confirm (through testing) that the product continues to perform as originally verified.

    Another benefit of selling certified products is the ability to investigate complaints on these products. Complaints can cover a variety of areas-false literature claims, nonperformance of a listed product, products that are not listed but represented as listed, etc. Through contracts with manufacturers, complaints will be investigated, and if valid, appropriate actions will be taken, including recalls and public notice of the problem.

    Today, millions of products from drinking water treatment systems and bottled water to commercial food equipment and plastic piping for plumbing systems have been certified by outside sources. You can rely on these products to meet strict public health and performance standards.

    About the Author:
    Nancy Culotta is general manager for the Dealer Program at NSF International, Ann Arbor, Michigan.

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